Unmanned aerial vehicle fleet management

ABSTRACT

An unmanned aerial vehicle (UAV) includes one or more sources of propulsion coupled to provide propulsion to the UAV, and a power source coupled to power the one or more sources of propulsion. A communication system is coupled to communicate with an external device, and a controller is coupled to the communication system, the power source, and the one or more sources of propulsion. The controller includes logic that when executed by the controller causes the UAV to perform operations, including: measuring a status of the UAV; sending the status of the UAV to the external device; receiving movement instructions from the external device; and engaging the one or more sources of propulsion to move the UAV from a first location to a second location within a storage facility.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/132,712, filed Sep. 17, 2018, the contents of which are incorporatedby reference herein in their entirety.

TECHNICAL FIELD

This disclosure relates generally to unmanned aerial vehicles (UAVs).

BACKGROUND INFORMATION

An unmanned vehicle, which may also be referred to as an autonomousvehicle, is a vehicle capable of travel without a physically-presenthuman operator. Various types of unmanned vehicles exist for variousdifferent environments. For instance, unmanned vehicles exist foroperation in the air, on the ground, underwater, and in space. Unmannedvehicles also exist for hybrid operations in which multi-environmentoperation is possible. Unmanned vehicles may be provisioned to performvarious different missions, including payload delivery,exploration/reconnaissance, imaging, public safety, surveillance, orotherwise. The mission definition will often dictate a type ofspecialized equipment and/or configuration of the unmanned vehicle.

Controlling unmanned vehicles can be problematic especially when thereare a large number of vehicles in close proximity. Crashes mayirreparably damage the vehicles, and pose a hazard for people in thevicinity of the moving vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the invention aredescribed with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified. Not all instances of an element arenecessarily labeled so as not to clutter the drawings where appropriate.The drawings are not necessarily to scale, emphasis instead being placedupon illustrating the principles being described.

FIG. 1 illustrates an unmanned aerial vehicle (UAV) having multiplemission segments, in accordance with an embodiment of the disclosure.

FIG. 2 is a perspective view illustration of a demonstrative unmannedaerial vehicle (UAV), in accordance with an embodiment of thedisclosure.

FIGS. 3A-3C illustrate storage facilities for UAVs, in accordance withseveral embodiments of the disclosure.

FIG. 4 is a method of controlling a plurality of UAVs, in accordancewith an embodiment of the disclosure.

DETAILED DESCRIPTION

Embodiments of a system, apparatus, and method for unmanned aerialvehicle (UAV) fleet management are described herein. In the followingdescription numerous specific details are set forth to provide athorough understanding of the embodiments. One skilled in the relevantart will recognize, however, that the techniques described herein can bepracticed without one or more of the specific details, or with othermethods, components, materials, etc. In other instances, well-knownstructures, materials, or operations are not shown or described indetail to avoid obscuring certain aspects.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Thus, theappearances of the phrases “in one embodiment” or “in an embodiment” invarious places throughout this specification are not necessarily allreferring to the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments.

When UAV operations reach significant scale, UAV operators (operators)need to maintain large fleets of UAVs. This is particularly true in thecase where UAVs are used for package delivery. A likely scenario for UAVstorage is for a UAV fleet to be stored in some large facility (e.g., awarehouse) during times of non-operation or during recharging. For theselarge scale storage systems, operators will need methods to manage thesefleets, including how to get a UAV in and out of that storage facility,and in the case of package delivery that originates at the samefacility, how to load packages onto aircraft in an efficient manner thatminimizes the time delay between a package being ready for delivery andthe customer receiving the package. Presented here are ways to move,organize, and dynamically rearrange UAVs inside of a storage facility.

There are several key high level points to this methodology: (1)aircraft may arrange or rearrange themselves (under their own power)inside of a facility dynamically based on the needs of the fleet; (2)aircraft used for delivery purposes may be staged fully charged waitingfor a package to minimize delivery time of a package to a customer; (3)these processes are not limited to 2-dimensional spaces, but can beextended to 3-dimensional spaces as well.

Here, UAVs returning from a mission would enter a facility through aknown ingress point (e.g., a door, hatch, opening, window, etc.) andhead for a landing pad. Also important to note is that landing pads mayalso contain aircraft recharging systems that automatically re-chargethe UAV batteries upon landing. Alternately, the landing pads maycontain battery exchange systems to remove a depleted battery from a UAVand install a fully charged battery (this may also be referred to as “acharging pad”).

In one embodiment, UAVs arriving to the facility would enter thefacility through an ingress point and fly to an unoccupied landing padthat is closest to the egress point. The UAV may land on any un-occupiedlanding pad or it may be commanded to land on a specific predefinedlanding pad by an external computing system (e.g., a UAV controlsystem). The UAV would wait until it is fully re-charged, then fly to anegress staging location where the UAV would wait until a package isloaded into/onto the UAV. Once the package is loaded into the UAV, itwould depart the facility through the egress point.

In some embodiments, power consumption upon return from a flight may berestricted or battery state of charge may be extremely low in somecases. In those cases, it is possible that the UAVs will land on alanding pad nearest the ingress point. If a multitude of aircraft withlow batteries accumulate near the ingress point, it may be necessary toclear the landing pads near the ingress point and keep them open forinbound aircraft. In this case, the first UAVs that landed near theingress point must be moved away from the ingress point. It may beprohibitive for this movement to be handled by human operators, and maybe expensive for this move to be handled by additional robotic systemsin the facility.

Therefore, the UAVs may be commanded to take flight inside the facilityand fly to a new unoccupied landing pad that is further away from theingress point, and is closer to the egress point. The command tore-position may be initiated from the UAV itself (based on on-boardsensors and controllers such as battery management systems) or it maycome from a centralized system. The command may be based on eventtriggers such as time_since_landed or battery_state_of_charge (othertriggers are possible as well).

As the UAVs continue to re-charge on landing pads, they may continue tore-organize towards the egress point, based on event triggers. Thisreorganization may be coordinated (by a central computing system) or itmay be ad-hoc and initiated by the UAVs. In the latter case, the UAV mayrequest to move to a new landing pad, and a central computing systemwould inform the UAV which landing pad to move to, and authorize it atime duration upon which to complete the move. By a central systemauthorizing the move, the central system can ensure that aircraft inmotion will not collide with other aircraft.

UAVs may navigate inside the facility using computer vision systems thatfollow visual reference markers or cues located throughout the facilityfor the UAV to refer to. These markers may be in the form of fiducialmarkings, light beacons, or others. There may be a marker that islocated at each landing pad, and act as an address for that landing pad(e.g., using a Quick Response code or the like). The UAV may use theseaddresses as navigational aids as it moves from one landing pad toanother. The UAV may optionally use navigational aids located not atlanding pads as a means of locating itself in the space and moving fromone position to another. Or, by simply recognizing specific visual cuesfrom inside the facility, the UAV has awareness of its location.

With this system and methodology in place, it is also possible that thelanding pads do not need to only be in a 2D planar array, but may alsobe in a 3D structure. Aircraft may be commanded to change verticallevels as well as lateral (XY) positions. In some embodiments, differenthorizontal and vertical pads are reserved for different class aircraft(e.g., larger or smaller wingspan, different charge rates, differentpayload capacities, etc.). Aircraft may be commanded to specificlocations based on their class of aircraft.

The package staging areas near the egress point may include simpleinfrastructure that facilitates efficient package loading of deliveryaircraft. Physically locating the package staging areas near the egresspoint will reduce the time from a package being ready for delivery andthe package being delivered.

The processes described herein may keep the aircraft staging areasoccupied with fully charged aircraft, and as soon as a spot at a stagingarea was vacated by a departing aircraft, the centralized system wouldcommand another aircraft to that position. The staging areas may alsohave re-charging systems that maintain aircraft at, or close to, 100%state of charge so the aircraft always have maximum battery capacity fora delivery mission. The system may let UAVs fly with less than 100%charge if the mission is short enough for the UAV to not run out ofbattery.

The following disclosure will discuss the embodiments described above,and other embodiments, as they relate to the figures.

FIG. 1 illustrates an example UAV 101 having multiple mission segments,in accordance with an embodiment of the disclosure. First, the controlsystem may pass mission instructions (which may be generated by a useror the like) to UAV 101. In the illustrated embodiment, UAV 101 has amission wherein it launches from an egress point in a nest location 105(e.g., a storage structure) and rises to its cruising altitude (missionsegment 1: hover profile), cruises to a waypoint 110 (mission segment 2:cruise profile), descends vertically to acquire a package and thenascends vertically back to its cruising altitude (mission segment 3:hover profile), cruises to a delivery destination 115 (mission segment4: cruise profile), descends vertically to deliver the package and thenascends vertically back to its cruising altitude (mission segment 5:hover profile), cruises back to nest location 105 (mission segment 6:cruise profile), and descends into an ingress point of a nest 105(mission segment 7: hover). In nest 105, UAV may be directed to acharging pad.

FIG. 2 is a perspective view illustration of a demonstrative UAV 200,according to an embodiment of the disclosure. UAV 200 is one possibleimplementation of UAV 101 illustrated in FIG. 1. UAV 200 is a fixed-wingUAV, which as the name implies, has a wing assembly 202 that cangenerate lift based on the wing shape and the vehicle's forward airspeedwhen propelled horizontally by cruise rotors 206. For instance, wingassembly 202 may have an airfoil-shaped cross section to produce anaerodynamic lift force on the UAV 200. The illustrated embodiment of UAV200 also includes hover rotors 212 to provide vertical propulsion.

The illustrated embodiment of UAV 200 includes a fuselage 204. In oneembodiment, fuselage 204 is modular and includes battery module 221 (oneexample of a power source), avionics module 223, a mission payloadmodule, and a fuselage cover. These modules may be detachable from eachother and mechanically securable to each other to contiguously form atleast a portion of the fuselage or UAV main body.

The battery module 221 may include a cavity for housing one or morebatteries 221 for powering UAV 200. The avionics module 223 housesflight control circuitry of UAV 200, which may include a controller 225and memory, communication systems 227 and antennas (e.g., cellulartransceiver, wife transceiver, etc.), and various sensors (e.g., globalpositioning sensor 229, inertial measurement unit (IMU) 223, computervision module 223 (e.g., LIDAR, image sensors, time-of-flight systems,etc.), a magnetic compass, etc.). The mission payload module housesequipment associated with a mission of UAV 200. For example, the missionpayload module may include a payload actuator for holding and releasingan externally attached payload. In another embodiment, the missionpayload module may include a camera/sensor equipment holder for carryingcamera/sensor equipment (e.g., camera, lenses, radar, LIDAR, pollutionmonitoring sensors, weather monitoring sensors, etc.). In yet anotherembodiment, the mission payload module may include an additional batteryholder to house additional or larger batteries for extended flighttimes. Of course, the mission payload module may provide mixed usepayload capacity (e.g., additional battery and camera equipment) for avariety of mix-use missions.

As illustrated, UAV 200 includes cruise rotors 206 positioned on wingassembly 202, which can each include a motor, shaft, and propeller, forpropelling UAV 200 horizontally. The illustrated embodiment of UAV 200further includes two boom assemblies 210 that secure to wing assembly202. Hover rotors 212 are mounted to boom assemblies 210. Hover rotors212 can each include a motor, shaft, and propeller, for providingvertical propulsion. Vertical propulsion units 212 may be used during ahover mode where UAV 200 is descending (e.g., to a delivery location),ascending (e.g., following a delivery), or maintaining a constantaltitude. Stabilizers 208 (or tails) may be included with UAV 200 tocontrol pitch and stabilize the UAV's yaw (left or right turns) duringcruise. In some embodiments, during cruise mode hover rotors 212 aredisabled and during hover mode cruise rotors 206 are disabled. In otherembodiments, hover rotors 212 are merely powered low during cruise modeand/or cruise rotors 206 are merely powered low during hover mode.

During flight, UAV 200 may control the direction and/or speed of itsmovement by controlling its pitch, roll, yaw, and/or altitude. Thrustfrom cruise rotors 206 is used to control air speed. For example, thestabilizers 208 may include one or more rudders 208 a for controllingthe UAV's yaw, and wing assembly 202 may include elevators forcontrolling the UAV's pitch and/or ailerons 202 a for controlling theUAV's roll. As another example, increasing or decreasing the speed ofall the propellers simultaneously can result in UAV 200 increasing ordecreasing its altitude, respectively.

As stated, UAV has one or more sources of propulsion (e.g., verticalpropulsion units 212 and cruise rotors 206), and a power source (e.g.,battery or hybrid energy system) coupled to power (e.g., with motors orthe like) the one or more sources of propulsion. Communication system227 (e.g., RF transceiver, Bluetooth transceiver, WiFi transceiver, orthe like) is coupled to communicate with an external device (e.g., thecommunication system of an aircraft control system—for examplecommunication system 339 in FIGS. 3A-3C). Controller 225 is coupled tocommunication system 227, power source (e.g., battery 221), and the oneor more sources of propulsion (e.g., vertical propulsion units 212 andcruise rotors 206), and controller 225 includes logic that when executedby controller 225 causes UAV 200 to perform a variety of operations. Theoperations may include: measuring a status of UAV 200 (e.g., byemploying voltage sensors to measure a battery condition, stress/strainsensors to measure a mechanical failure, retrieving UAVspecifications—wingspan, length, model number, etc.—from the internalmemory of the UAV, etc.). The status of UAV 200 may be sent to theexternal device (e.g., UAV control system), and, in response to sendingthe status, the external device may send movement instructions back toUAV 200. UAV 200 may receive movement instructions from the externaldevice, and in response to receiving the movement instructions, engagethe one or more sources of propulsion to move UAV 200 from a firstlocation (e.g., a first charging pad, maintenance pad, or staging area)to a second location (e.g., a second charging pad, maintenance pad,storage location, or staging area) within a storage facility. In someembodiments, the status includes a power source charge level (e.g., 5%battery charge, 50% battery charge, 90% battery charge, etc.), and themovement instructions maybe received when the power source charge levelis less than a threshold level (e.g., less than 20% charge). In thisembodiment, the first location may be closer to an egress point than thesecond location. Put another way, the UAV control system may determinethat UAV 200 has too little charge to complete a mission, andaccordingly, the control system may move UAV 200 away from an egresspoint to charge, so it is not in the way of other incoming or outgoingUAVs. Conversely, UAV 200 may report a status when the power sourcecharge level is greater than one or more thresholds, and UAV 200 may bemoved closer to the egress point. Other UAVs (which may have a lowerpower level) on pads closer to the egress point may be directed to moveout of the way of UAV 200 once it reaches the threshold charge level.Mid-flight UAVs may also be requested to move out of the fight path ofUAV 200, while UAV 200 is flying.

In one embodiment, the status sent from UAV 200 includes a maintenancerequest, and the second location may include a maintenance pad (e.g., aplace where UAV 200 may be taken out of service, or repaired). However,in some embodiments, the status update sent from UAV 200 may include anindicator of geographic proximity (e.g., a specific signal is sent whenthe UAV is within 30 feet) to the storage location (e.g., a warehouseholding all of the UAVs) after completing a mission, and the movementinstructions include directions to a charging pad that is unoccupied.Put another way, when a returning UAV 200 reaches a threshold distancefrom the storage facility, it may send a signal to the UAV controlsystem/facility. The control facility may send instructions to directthe incoming UAV 200 to an optimal charging pad, and the charging padmay be chosen based, at least in part, on a power source charge level ofUAV 200.

In some embodiments, UAV 200 may include computer vision system 223coupled to controller 225. UAV 200 may use the computer vision system223 to recognize fiducial markers positioned within the storagefacility, and in response to recognizing the fiducial markers, directUAV 200 to a landing pad or the like.

Many variations on the illustrated fixed-wing UAV are possible. Forinstance, fixed-wing UAVs may include more or fewer propellers, and/ormay utilize a ducted fan or multiple ducted fans for propulsion.Further, UAVs with more wings (e.g., an “x-wing” configuration with fourwings), are also possible. Although FIG. 2 illustrates one wing assembly202, two boom assemblies 210, two forward propulsion units 206, and sixvertical propulsion units 212 per boom assembly 210, it should beappreciated that other variants of UAV 200 may be implemented with moreor less of these components. Furthermore, the guidance systems andmethods described herein may be used with other types of UAVs, manned orunmanned vehicles in general, or otherwise.

It should be understood that references herein to an “unmanned” aerialvehicle or UAV can apply equally to autonomous and semi-autonomousaerial vehicles. In a fully autonomous implementation, all functionalityof the aerial vehicle is automated; e.g., pre-programmed or controlledvia real-time computer functionality that responds to input from varioussensors and/or pre-determined information. In a semi-autonomousimplementation, some functions of an aerial vehicle may be controlled bya human operator, while other functions are carried out autonomously.Further, in some embodiments, a UAV may be configured to allow a remoteoperator to take over functions that can otherwise be controlledautonomously by the UAV. Yet further, a given type of function may becontrolled remotely at one level of abstraction and performedautonomously at another level of abstraction. For example, a remoteoperator may control high level navigation decisions for a UAV, such asspecifying that the UAV should travel from one location to another(e.g., from a warehouse in a suburban area to a delivery address in anearby city), while the UAV's navigation system autonomously controlsmore fine-grained navigation decisions, such as the specific route totake between the two locations, specific flight controls to achieve theroute and avoid obstacles while navigating the route, and so on.

FIGS. 3A-3C illustrate storage facilities (e.g., a “nest” location 105from FIG. 1) for UAVs, in accordance with several embodiments of thedisclosure. One of skill in the art will appreciate that thecomponents/features depicted in FIGS. 3A-3C are not mutually exclusiveand can used interchangeably across storage facilities in accordancewith the teachings of the present disclosure.

FIG. 3A illustrates a first enclosed storage facility 331 with separateingress and egress points (e.g., windows that may open and close) onopposite sides of the structure. Also depicted are parts of a controlsystem (e.g., a “control tower”) for the UAVs including network 333,storage 335, controller 337 (e.g., servers in a distributed system,local computer, a combination thereof, or the like), and communicationsystem 339 (e.g., RF transceiver, WiFi transceiver, Bluetooth, or thelike). Charging pads 341, maintenance pads 345, and staging area 343 arealso depicted.

In the illustrated embodiment, the control system for the UAVs receives,with a receiver (included in communication system 339), a status updatefrom one of the UAVs. The control system may calculate with controller337 moving instructions based on the status update. The system may thensend, using communication system 339, the movement instructions to theone or more UAVs, and the movement instructions include directions tomove the UAVs from a first location (e.g., a first charging pad 341,maintenance pad 345, staging area 343, or the like) to a second location(e.g., a second charging pad 341, maintenance pad 345, staging area 343,or the like) within storage facility 331A. Movement instructions may beprovided to rearrange the UAVs for the reasons described above. In someembodiments, the status update may include a power source charge level(e.g., battery level) of the UAV, and the movement instructions arecalculated, at least in part, based on the power source charge level(e.g., determining that a power source charge level is less than a firstthreshold level). In the depicted embodiment, the movement instructionsinclude sending directions to move the UAV to the second location awayfrom an egress point, thus freeing up space near the egress points forfully charged aircraft. This may minimize time for fully charged UAVs tofly to staging areas 343 and complete missions. Conversely, in someembodiments, the system here may promote moving fully charged UAVstowards the egress point—as shown, all of the fully charged UAVs areclustered proximate to the egress point. For example, calculating themovement instructions may include determining that the power sourcecharge level is above a threshold level, and sending the movementinstructions includes sending directions to move the UAV to the secondlocation (e.g., staging area 343) proximate to an egress point. UAVs maybe moved one by one towards the egress point as they become more fullycharged.

In some embodiments, one or more UAVs may need to be moved toaccommodate new aircraft entering the structure. For example, movementinstructions may be sent to a second UAV that is positioned in a secondlocation, to move to a third location, prior to sending the movementinstructions to a first UAV that is positioned in a first location, tomove to the second location. In this example, the second UAV may be morefully charged than the first UAV, or have a new battery pack attached,and the third location is closer to the egress point (since the secondUAV is more mission-ready).

In some embodiments, the status update set from the UAV may include amaintenance request (e.g., because sensors in the UAV detect a faultyrotor, a battery that is not able to maintain a charge, a communicationsystem that is not working properly, etc.), and the second locationincludes maintenance pad 345.

FIG. 3B illustrates a different embodiment of storage facility 331Bincluding a design where the ingress and egress points are the same—theaircraft come and go through the same windows. In the depicted example,since there are shared ingress and egress points, the communicationsystem that controls the UAV fleet may also have to control air trafficthrough the shared openings. For example, the system may make sure thata single UAV flies through a single opening to avoid crashes. The systemmay also have UAVs, with sufficient battery, pause outside the structureto wait their turn to enter the building. Similarly, if a UAV has verylittle charge left or is damaged after completing a mission, the controlsystem may pause all air traffic in and out of the building, as well asclear a landing pad next to the openings in order for the damaged UAV tomake a quick landing. In some embodiments, the UAV control system (orthe UAVs themselves) may calculate their trajectory/vector to a new pador location and prevent other UAVs from entering this flight path. Thismay be accomplished by the UAV sending the flight path to the otherUAVs, or the control system preventing UAVs from entering the path. Itis appreciated that the control system may send instruction to one ormore UAVs simultaneously. In some embodiments, UAVs and/or the controlsystem are programmed to keep UAVs a predetermined distance apart toavoid crashes.

FIG. 3C illustrates a different embodiment of storage facility 331Cwhere there are no walls physically enclosing the structure—the ingressand egress points surround the storage facility on all sides. Putanother way, the storage facility 331C is a geographic area containingat least one charging pad 341, maintenance pad 345, or staging area 343.Depicted here, the charging pads 341 are disposed on the floor of adesignated area, and the staging areas 343 are positioned proximate toone side of the area. Similarly, communication system 339 is disposed onthe floor with the pads. Also depicted is a multilayer rack 347 (e.g., astorage location) for housing UAVs, which may include charging, storage,and/or maintenance pads. Multilayer rack 347 may be used for long termstorage (e.g., for UAVs that will be out of service for a day, a week, amonth, or any other amount of time). This configuration depicted in FIG.3C may be used in emergency response situations (e.g., to deliverfood/water) where buildings to house the UAVs are in short supply.

FIG. 4 is a method 400 of unmanned aerial vehicle (UAV) operation, inaccordance with an embodiment of the disclosure. One of ordinary skillin the art will appreciate that blocks 401-407 may occur in any orderand even in parallel. Additionally, blocks may be added to, or removedfrom, method 400, in accordance with the teachings of the presentdisclosure.

Block 401 shows measuring a status of the UAV using a controller in theUAV. In some embodiments, measuring the status includes measuring apower source charge level of the UAV using voltage sensors or the like.In another or the same embodiment, measuring a status may includemeasuring damage to the UAV, or degradation of the electronic componentswithin. Similarly, measuring a status may include the UAV recalling itsmodel number, type, dimensions or the like. In one embodiment, thestatus may include a package/payload load status. In another embodiment,the status may include a geographic proximity to the storage location(e.g., within 30 feet of an entrance to the storage facility) aftercompleting a mission.

Block 403 illustrates sending the status of the UAV to an externaldevice using a communication system deposed in the UAV. As depicted inFIGS. 3A-3C, the status may be received by a communication system thatis part of the UAV control system (e.g., a control tower for the UAVs)in the storage facility. One of skill in the art will appreciate thatthere may be different communication types used during the differentstages of the UAV's flight. For example, during a mission, RFcommunication or GPS may be used to direct the UAV through open space.However, within a storage facility, fiducial markers and WiFi/Bluetoothmay be used to direct the UAV in the smaller enclosed area, and may beused to achieve better location accuracy. In some embodiments, thecontrol system may switch navigation modes for the UAV as it isentering/leaving the storage facility.

Block 405 depicts in response to sending the status, receiving movementinstructions from the external device with the communication system inthe UAV. The instructions may be received with an antenna in the UAV. Itis appreciated that the UAV control system may generate the movementinstructions immediately after receiving the status, or a delay may bepresent until the system deems it necessary to send the movement data tothe UAV. In some embodiments, movement instructions are not sent untilinformation from more than one UAV is received (e.g., the system may notelect to move a UAV until another UAV need its spot on a charging,maintenance, or staging pad).

Block 407 shows, in response to receiving the movement instructions,engaging one or more sources of propulsion to move the UAV from a firstlocation to a second location within a storage facility. In someembodiments, the control system sends the movement instructions when thepower source charge level in the UAV is less than a thresholdlevel—telling the UAV to move to a different location because its chargeis too low. In some embodiments, this may include moving the UAV awayfrom an egress point so it does not interfere with other outgoingaircraft. Conversely, the UAV may be moved closer to the egress point asthe UAV has greater power reserves. In some embodiments, the UAV may bemoved based on its model type and dimensions (e.g., to a charging padthat fits the specific model of UAV).

The processes explained above are described in terms of computersoftware and hardware. The techniques described may constitutemachine-executable instructions embodied within a tangible ornon-transitory machine (e.g., computer) readable storage medium, thatwhen executed by a machine will cause the machine to perform theoperations described. Additionally, the processes may be embodied withinhardware, such as an application specific integrated circuit (“ASIC”) orotherwise.

A tangible machine-readable storage medium includes any mechanism thatprovides (i.e., stores) information in a non-transitory form accessibleby a machine (e.g., a computer, network device, personal digitalassistant, manufacturing tool, any device with a set of one or moreprocessors, etc.). For example, a machine-readable storage mediumincludes recordable/non-recordable media (e.g., read only memory (ROM),random access memory (RAM), magnetic disk storage media, optical storagemedia, flash memory devices, etc.).

The above description of illustrated embodiments of the invention,including what is described in the Abstract, is not intended to beexhaustive or to limit the invention to the precise forms disclosed.While specific embodiments of, and examples for, the invention aredescribed herein for illustrative purposes, various modifications arepossible within the scope of the invention, as those skilled in therelevant art will recognize.

These modifications can be made to the invention in light of the abovedetailed description. The terms used in the following claims should notbe construed to limit the invention to the specific embodimentsdisclosed in the specification. Rather, the scope of the invention is tobe determined entirely by the following claims, which are to beconstrued in accordance with established doctrines of claiminterpretation.

What is claimed is:
 1. A method of controlling a plurality of unmannedaerial vehicles (UAVs), the method comprising: receiving a status from afirst UAV of the plurality of UAVs, wherein the status includes a powersource charge level of the first UAV; calculating movement instructionsbased on the status; and sending the movement instructions to the firstUAV, wherein the movement instructions include directions to move thefirst UAV from a first location within a storage facility to a secondlocation, wherein the first UAV is selected to move to the secondlocation based, at least in part, upon the power source charge level ofthe first UAV, wherein the second location has a shorter flight time toan egress point of the storage facility or to a staging area, relativeto the first location, wherein the movement instructions promotemovement of the first UAV towards the egress point or towards thestaging area over others of the UAVs having lesser charge levels thanthe first UAV at the first location.
 2. The method of claim 1, whereinthe movement instructions instruct the first UAV to move to the secondlocation when the power source charge level is greater than a firstthreshold level and the power source charge level of the first UAV isgreater than that of the other UAVs at the first location.
 3. The methodof claim 1, wherein the storage facility is a geographic area thatincludes charging pads for charging the UAVs.
 4. The method of claim 3,wherein the storage facility does not include walls that physicallyenclose the storage facility.
 5. The method of claim 1, wherein thestaging area comprises an area for loading the UAVs with packages fordelivery via the UAVs.
 6. The method of claim 1, wherein the firstlocation includes first charging pads for charging the UAVs at the firstlocation within the storage facility.
 7. The method of claim 6, whereinthe second location includes second charging pads for charging the UAVsat the second location.
 8. At least one machine-readable storage mediumthat provides instructions that, when executed by a machine, will causethe machine to perform operations comprising: obtaining a status for afirst UAV, wherein the status includes a power source charge level ofthe first UAV; calculating movement instructions based on the status;and instructing the first UAV, based upon the movement instructions, tomove from a first location within a storage facility to a secondlocation, wherein the second location is selected based, at least inpart, upon the power source charge level, wherein the second location isselected to have a shorter flight time to an egress point of the storagefacility or to a staging area, relative to the first location, when thepower source charge level is greater than a first threshold level topromote moving the first UAV towards the egress point or towards thestaging area over other UAVs having lesser charge levels than the firstUAV at the first location within the storage facility.
 9. The at leastone machine-readable storage medium of claim 8, wherein the storagefacility is a geographic area that includes charging pads for chargingthe first UAV and the other UAVs.
 10. The at least one machine-readablestorage medium of claim 9, wherein the storage facility does not includewalls that physically enclose the storage facility.
 11. The at least onemachine-readable storage medium of claim 8, wherein the staging areacomprises an area for loading the first UAV or the other UAVs withpackages for delivery.
 12. The at least one machine-readable storagemedium of claim 8, wherein the second location is selected to have alonger flight time to the egress point of the storage facility or to thestaging area, relative to the first location, when the power sourcecharge level of the first UAV is less than a second threshold level tofree up space proximate to the egress point or the staging area forother UAVs having greater charge levels than the first UAV that are moremission-ready.
 13. The at least one machine-readable storage medium ofclaim 12, wherein the status includes a maintenance request and thesecond location is a maintenance pad when the first UAV requiresmaintenance.
 14. The at least one machine-readable storage medium ofclaim 8, wherein the status includes an indicator of a geographicproximity of the first UAV after completing a mission, and wherein themovement instructions include directions to a charging pad that isunoccupied.
 15. The at least one machine-readable storage medium ofclaim 8, further providing instructions that, when executed by themachine, will cause the machine to perform further operations,comprising: recognizing, using a computer vision system, fiducialmarkers positioned within the storage facility; and moving the first UAVto the second location with aid from the fiducial markers.
 16. At leastone machine-readable storage medium that provides instructions that,when executed by a machine, will cause the machine to perform operationsfor controlling a plurality of unmanned aerial vehicles (UAVs), theoperations comprising: receiving a status from a first UAV of theplurality of UAVs, wherein the status includes a power source chargelevel of the first UAV; calculating movement instructions based on thestatus; and sending the movement instructions to the first UAV, whereinthe movement instructions include directions to move the first UAV froma first location within a storage facility to a second location, whereinthe first UAV is selected to move to the second location based, at leastin part, upon the power source charge level of the first UAV, whereinthe second location has a shorter flight time, relative to the firstlocation, to an egress point of the storage facility or to a stagingarea, wherein the movement instructions promote movement of the firstUAV towards the egress point or towards the staging area over others ofthe UAVs having lesser charge levels than the first UAV at the firstlocation.
 17. The least one machine-readable storage medium of claim 16,wherein the movement instructions instruct the first UAV to move to thesecond location when the power source charge level is greater than afirst threshold level and the power source charge level of the first UAVis greater than that of the other UAVs at the first location.
 18. Theleast one machine-readable storage medium of claim 16, wherein thestorage facility is a geographic area that includes charging pads forcharging the UAVs.
 19. The least one machine-readable storage medium ofclaim 16, wherein the staging area comprises an area for loading theUAVs with packages for delivery via the UAVs.
 20. An unmanned aerialvehicle (UAV), comprising: one or more sources of propulsion coupled toprovide propulsion to the UAV; a power source coupled to power the oneor more sources of propulsion; a communication system coupled to thepower source to communicate with an external device; and a controllercoupled to the communication system, the power source, and the one ormore sources of propulsion, wherein the controller includes logic thatwhen executed by the controller causes the UAV to perform operations,including: measuring a status of the UAV, the status including a powersource charge level of the UAV; sending the status of the UAV to theexternal device; receiving movement instructions from the externaldevice; and in response to receiving the movement instructions, engagingthe one or more sources of propulsion to move the UAV from a firstlocation within a storage facility to a second location, wherein thesecond location is selected based, at least in part, upon the powersource charge level, wherein the second location is selected to have ashorter flight time to an egress point of the storage facility or to astaging area, relative to the first location, when the power sourcecharge level is greater than a first threshold level to promote movingthe UAV towards the egress point or the staging area over other UAVshaving lesser charge levels.